Air cleaner

ABSTRACT

An air cleaner includes a housing, a filter element, a fan wheel and a motor. The fan wheel includes a rear end plate, a front end plate, and a plurality of fan blades that are mounted between the rear end plate and the front end plate. A central opening of the front end plate is defined as an airflow inlet of the fan wheel. An airflow outlet of the fan wheel is defined between an outer edge of the front end plate and an outer edge of the rear end plate. The rear end plate has an outer diameter defined as D 1.  The front end plate has an outer diameter defined as D 2.  D 2  is less than D 1,  and 
     
       
         
           
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     The air cleaner can eliminate a self-loss area of jet streams of the fan wheel and attain the object of reducing noise, without reducing air volume.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The present invention relates to an air cleaner, and more particularly to a novel air cleaner.

2. Description of the Prior Art

A fan wheel functions as the power source of an air cleaner, so its structural design will directly affect the aerodynamic performance. The main parameters of the aerodynamic performance are air volume and noise. The design of the fan wheel structure aims to have a large air volume and a small noise. An air duct system of a centrifugal fan wheel without a volute casing is generally applied to the power mechanism of most home air cleaners, including an air duct and a fan wheel. The air duct system is capable of achieving equal air outflow and providing a straight air intake direction and a straight air outlet direction. This structure meets the requirements of most home air clearers. Generally, the outer diameters of most centrifugal fan wheels are designed to be a single grade outer diameter. Through the simulation analysis of aerodynamics, it can be found that the distribution of the air outlet cross section of jet streams of the fan wheel is not equal for the air duct system of the centrifugal fan wheel without the volute casing. Self-loss jet streams will be caused when air streams are near to an air intake opening, which results in the major source of noise to affect the user experience of the air cleaner. The general way to reduce noise is to reduce the air volume.

In addition, due to the centrifugal action of the fan wheel, the air duct may have the phenomenon of flow around. The increase in resistance along the path leads to a decrease in air volume. Further, due to the uneven velocity of the centrifugal air stream, the loss of air volume is aggravated.

SUMMARY OF THE INVENTION

In view of the shortcomings of the prior art, the primary object of the present invention is to provide an air cleaner that reduces noise and improves user experience without reducing air volume.

In order to achieve the above object, the present invention adopts the following technical solutions:

An air cleaner comprises a housing having an air duct. A filter element, a fan wheel and a motor are disposed sequentially from an air inlet to an air outlet of the air duct. The fan wheel includes a rear end plate that cooperates with a drive shaft of the motor, an annular front end plate, and a plurality of fan blades that are mounted at equal intervals between the rear end plate and the front end plate. A central opening of the front end plate is defined as an airflow inlet of the fan wheel. An airflow outlet of the fan wheel is defined between an outer edge of the front end plate and an outer edge of the rear end plate. The rear end plate has an outer diameter defined as D1. The front end plate has an outer diameter defined as D2. D2 is less than D1 and

$0.88 < \frac{D\; 2}{D\; 1} < {0.92.}$

Preferably, an outer end of each fan blade has a two-stage design, including a first outer edge and a second outer edge. The first outer edge is connected to the outer edge of the rear end plate. The second outer edge is connected to the outer edge of the front end plate. A curved outer edge is connected between the first outer edge and the second outer edge.

Preferably, each fan blade has an air outlet angle of 60° to 68°, an air intake angle of 58° to 64°, and an extension angle of 54° to 64°. The number of the fan blades is 9-11. The air outlet angle of the fan blade is the included angle between an outer edge tangent of the fan blade and the diameter crossing the tangent point of the outer edge tangent of the fan wheel. The air intake angle is the included angle between an inner edge tangent of the fan blade and the diameter crossing the tangent point of the inner edge tangent of the fan wheel. The extension angle of the fan blade is the included angle between the radius crossing the fan blade inner end of the fan wheel and the radius crossing the fan blade outer end of the fan wheel.

Preferably, the air outlet angle of the fan blade is 64°, the air intake angle of the fan blade is 62°, the extension angle of the fan blade is 59°, and the number of the fan blades is 9.

Preferably, in a radial direction of the fan wheel, a curved surface is formed between the fan blade outer end and the fan blade inner end. In an axial direction of the fan wheel, each fan blade is inclined along the airflow inlet toward the outer edge of the rear end plate to form an inclined surface that is a curved surface.

Preferably, a central portion of the rear end plate is provided with a guide boss protruding toward the airflow inlet. A guide slope is formed between an outer edge of the guide boss and the outer edge of the rear end plate.

Preferably, the rear end plate is provided with a plurality of pairs of ribs corresponding in position to the fan blades for retaining the fan blades.

Preferably, the air cleaner further comprises a guide unit. The guide unit is mounted in the air duct and located between the air outlet and the motor. The guide unit includes an outer mounting seat, an inner mounting seat, and a plurality of guide blades that are mounted at equal intervals between the outer mounting seat and the inner mounting seat. Each guide blade has a guide fan inner end connected to an outer circumference of the inner mounting seat and a guide blade outer end connected to an inner side of the outer mounting seat. The outer mounting seat is mounted on a side wall of the air duct. A guide direction of each guide blade is deflected from an inner side to an outer side of the guide unit.

Preferably, the guide blade outer end has a width of 18-22 mm. The guide blade inner end has a width of 28-32 mm. Each guide blade has a height of 37-41 mm.

Preferably, the guide blade inner end has an air intake angle of 60° to 70° and an air outlet angle of 80° to 90°. The guide blade outer end has an air intake angle of 60° to 70° and an air outlet angle of 80° to 90°. The air intake angle of the guide blade inner end is the included angle between an inner edge tangent of the guide blade inner end and a rotation axis of the fan wheel. The air outlet angle of the guide blade inner end is the included angle between an outer edge tangent of the guide blade inner end and a vertical plane of the rotation axis of the fan wheel. The air intake angle of the guide blade outer end is the included angle between an inner edge tangent of the guide blade outer end and the rotation axis of the fan wheel. The air outlet angle of the guide blade outer end is the included angle between an outer edge tangent of the guide blade outer end and the vertical plane of the rotation axis of the fan wheel.

In the present invention, the outer diameter of the front end plate of the fan wheel is less than the outer diameter of the rear end plate, thereby reducing the absolute velocity of the fan blades in the area of the airflow inlet to eliminate a self-loss area of jet streams of the fan wheel. The noise is reduced without reducing air volume, and the user experience is improved.

In addition, the design of the air outlet angle, the air inlet angle and the extension angle of each fan blade and the number of the fan blades limit the main parameter range, which can ensure the stability of the working of the fan wheel. The guide unit is disposed between the air outlet of the air duct and the motor, providing a guide function. The air directed out by the fan wheel is centered toward the middle of the air outlet to avoid the phenomenon of flow around, thereby reducing the loss of air volume, ensuring uniform distribution of air velocity and improving the user experience.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view in accordance with a preferred embodiment of the present invention;

FIG. 2 is a perspective view of the fan wheel of the present invention;

FIG. 3 is a front view of the fan wheel of the present invention;

FIG. 4 is a sectional view taken along line A-A of FIG. 3;

FIG. 5 is a perspective view of the guide unit of the present invention;

FIG. 6 is a top view of the guide unit of the present invention;

FIG. 7 is a sectional view taken along line B-B of FIG. 6; and

FIG. 8 is a schematic view showing the flow of air in accordance with the preferred embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings.

Referring to FIGS. 1 to 8, an air cleaner in accordance with a preferred embodiment of the present invention comprises a housing 1 having an air duct 11. A filter element 2, a fan wheel 3 and a motor 4 are disposed sequentially from an air inlet 12 to an air outlet 13 of the air duct 11. In the working state, the motor 4 drives the fan wheel 3 to rotate. The air inside the fan wheel 3 is centrifugally directed out and flows along the air duct 11 toward the air outlet 13 to form a negative pressure area inside the fan wheel 3. The air outside the housing 1 is introduced to the filter element 2 via the air inlet 12 of the air duct 11. The particulates and harmful gases in the air are absorbed by the filter element 2. The clean air flows through the filter element 2 to the negative pressure area to be centrifugally directed out by the fan wheel 3, such that the air is circulated and purified.

Referring to FIGS. 2 to 4, the fan wheel 3 includes a rear end plate 31 that cooperates with a drive shaft of the motor 4, an annular front end plate 32, and a plurality of fan blades 33 that are mounted at equal intervals between the rear end plate 31 and the front end plate 32. A central opening of the front end plate 32 is defined as an airflow inlet 34 of the fan wheel 3. An airflow outlet 35 of the fan wheel 3 is defined between the outer edge of the front end plate 32 and the outer edge of the rear end plate 31. The outer diameter of the rear end plate 31 is defined as D1. The outer diameter of the front end plate 32 is defined as D2. D2 is less than D1, and

$0.88 < \frac{D\; 2}{D\; 1} < {0.92.}$

In this embodiment, D1 is 148 mm and D2 is 136 mm. Since the jet streams of the fan wheel 3 are centered in the area of the airflow inlet 34, reducing the outer diameter of the front end plate 32 is equivalent to reducing the outer diameter of the fan blades 33 to reduce the absolute velocity of the fan blades 33 in the area of the airflow inlet 34 to thereby eliminate a self-loss area of jet streams of the fan wheel 3 and attain the object of reducing noise.

The outer end of the fan blade 33 has a two-stage design, including a first outer edge 331 and a second outer edge 332. The first outer edge 331 is connected to the outer edge of the rear end plate 31. The second outer edge 332 is connected to the outer edge of the front end plate 32. A curved outer edge 333 is connected between the first outer edge 331 and the second outer edge 332 to achieve a smooth transition from the first outer edge 331 to the second outer edge 332.

The air outlet angle of the fan blade 33 is defined as α1. The air intake angle of the fan blade 33 is defined as α2. The extension angle of the fan blade 33 is defined as α3. α1 is in the range of 60° to 68°. α2 is in the range of 58° to 64°. α3 is in the range of 54° to 64°. The number of the fan blades 33 is 9-11. In this embodiment, α1 is 64°, α2 is 62°, α3 is 59°, and the number of the fan blades 33 is 9. The air outlet angle al of the fan blade 33 is the included angle between an outer edge tangent of the fan blade 33 and the diameter crossing the tangent point of the outer edge tangent of the fan wheel 3. The air intake angle α2 is the included angle between an inner edge tangent of the fan blade 33 and the diameter crossing the tangent point of the inner edge tangent of the fan wheel 3. The extension angle α3 of the fan blade 33 is the included angle between the radius crossing the fan blade inner end 33B of the fan wheel 3 and the radius crossing the fan blade outer end 33A of the fan wheel 3. A large number of fan blades 33 (more than 11) may cause difficulty in mold design. A small number of fan blades 33 (less than 9) may result in poor performance of the fan wheel 3.

In the radial direction of the fan wheel 3, a curved surface is formed between the fan blade outer end 33A and the fan blade inner end 33B. In the axial direction of the fan wheel 3, the fan blade 33 is inclined along the airflow inlet 34 toward the outer edge of the rear end plate 31 to form an inclined surface that is a curved surface. The fan blade 33 having the above-mentioned shape realizes the guiding of the air stream introduced from the airflow inlet 34, so that the air stream flows out from the airflow outlet 35 in a spiral manner to increase the included angle between the air stream in the radial direction and the axial direction of the air duct 11 and the side wall of the air duct 11. The air stream obliquely flows to the side wall of the air duct 11, thereby reducing the kinetic energy loss of the air stream and increasing the air volume of the air cleaner.

The central portion of the rear end plate 31 is provided with a guide boss 311 protruding toward the airflow inlet 34. A guide slope 312 is formed between the outer edge of the guide boss 311 and the outer edge of the rear end plate 31. When the air stream enters the fan wheel 3 from the airflow inlet 34 and flows toward the rear end plate 31, the air stream is deflected toward the airflow outlet 35 under the blocking and guiding of the guide boss 311 and the guide slope 312, thereby avoiding the impact of the air stream with the rear end plate 31, reducing the kinetic energy loss of the air, reducing noise and increasing air volume.

The rear end plate 31 is provided with a plurality of pairs of ribs 313 corresponding in position to the fan blades 33 for retaining the fan blades 33, so that the fan blades 33 are retained on the rear end plate 31 to improve the structural stability and prevent the fan blades 33 from shaking. The present invention further comprises a guide unit 5 as shown in FIGS. 5-7. The guide unit 5 is mounted in the air duct 11 and located between the air outlet 13 and the motor 4. The guide unit 5 includes an outer mounting seat 51, an inner mounting seat 52, and a plurality of guide blades 53 that are mounted at equal intervals between the outer mounting seat 51 and the inner mounting seat 52. Each guide blade 53 has a guide fan inner end 53A connected to the outer circumference of the inner mounting seat 52 and a guide blade outer end 53B connected to the inner side of the outer mounting seat 51. The outer mounting seat 51 is mounted on the side wall of the air duct 11. The guide direction of the guide blade 53 is deflected from the inner side to the outer side of the guide unit 5. The guide blade 53 having the above-mentioned shape realizes the guiding of the air from the input end (the lower end in FIG. 8) of the guide unit 5, so that the air flows out from the output end (the upper end in FIG. 8) of the guide unit 5 in a spiral manner to be centered in the middle, avoiding the phenomenon of flow around, reducing the loss of air volume and ensuring uniform distribution of air velocity.

The width of the guide blade outer end 53B is 18-22 mm. The width of the guide blade inner end 53A is 28-32 mm. The height of the guide blade 53 is 37-41 mm. The air intake angle of the guide blade inner end 53A is in the range of 60° to 70°. The air outlet angle of the guide blade inner end 53A is in the range of 80° to 90°. The air intake angle of the guide blade outer end 53B is in the range of 60° to 70°. The air outlet angle of the guide blade outer end 53B is in the range of 80° to 90°. The air intake angle of the guide blade inner end 53A is the included angle between an inner edge tangent of the guide blade inner end 53A and a rotation axis of the fan wheel 3. The air outlet angle of the guide blade inner end 53A is the included angle between an outer edge tangent of the guide blade inner end 53A and the vertical plane of the rotation axis of the fan wheel 3. The air intake angle of the guide blade outer end 53B is the included angle between an inner edge tangent of the guide blade outer end 53B and the rotation axis of the fan wheel 3. The air outlet angle of the guide blade outer end 53B is the included angle between an outer edge tangent of the guide blade outer end 53B and the vertical plane of the rotation axis of the fan wheel 3.

As shown in FIG. 8, in the working state, the motor 4 drives the fan wheel 3 to rotate. The air inside the fan wheel 3 is centrifugally directed out and flows along the air duct 11 toward the air outlet 13 to form a negative pressure area inside the fan wheel 3. The air outside the housing 1 is introduced to the filter element 2 via the air inlet 12 of the air duct 11. The particulates and harmful gases in the air are absorbed by the filter element 2. The clean air flows through the filter element 2 to the negative pressure area to be centrifugally directed out by the fan wheel 3. The structural design of the fan wheel 3 reduces the absolute velocity of the fan blades 33 in the area of the airflow inlet 34 to thereby eliminate a self-loss area of jet streams of the fan wheel 3 and attain the object of reducing noise. The included angle between the air stream in the radial direction and the axial direction of the air duct 11 and the side wall of the air duct 11 is increased, so that the air stream is directed to the guide unit 5 in a spiral manner and then guided by the guide unit 5. The air stream is centered toward the middle of the air outlet 13, so that the clean air is evenly discharged out of the air outlet 13, thereby achieving the circulation and purification of the air.

In the present invention, the outer diameter of the front end plate 32 of the fan wheel 3 is less than the outer diameter of the rear end plate 31, thereby reducing the absolute velocity of the fan blades 33 in the area of the airflow inlet 34 to eliminate a self-loss area of jet streams of the fan wheel 3. The noise is reduced without reducing the air volume, and the user experience is improved.

In addition, the design of the air outlet angle, the air inlet angle and the extension angle of each fan blade 33 and the number of the fan blades 33 limit the main parameter range, which can ensure the stability of the working of the fan wheel 3. The guide unit 5 is disposed between the air outlet 13 of the air duct 11 and the motor 4, providing a guide function. The air directed out by the fan wheel 3 is centered toward the middle of the air outlet 13 to avoid the phenomenon of flow around, reducing the loss of air volume, ensuring uniform distribution of air velocity and improving the user experience.

Although particular embodiments of the present invention have been described in detail for purposes of illustration, various modifications and enhancements may be made without departing from the spirit and scope of the present invention. Accordingly, the present invention is not to be limited except as by the appended claims. 

What is claimed is:
 1. An air cleaner, comprising a housing having an air duct, a filter element, a fan wheel and a motor being disposed sequentially from an air inlet to an air outlet of the air duct; the fan wheel including a rear end plate that cooperates with a drive shaft of the motor, an annular front end plate, and a plurality of fan blades that are mounted at equal intervals between the rear end plate and the front end plate; a central opening of the front end plate being defined as an airflow inlet of the fan wheel, an airflow outlet of the fan wheel being defined between an outer edge of the front end plate and an outer edge of the rear end plate; the rear end plate having an outer diameter defined as D1, the front end plate having an outer diameter defined as D2, D2 being less than D1 and $0.88 < \frac{D\; 2}{D\; 1} < {0.92.}$
 2. The air cleaner as claimed in claim 1, wherein an outer end of each fan blade has a two-stage design, including a first outer edge and a second outer edge, the first outer edge is connected to the outer edge of the rear end plate, the second outer edge is connected to the outer edge of the front end plate, and a curved outer edge is connected between the first outer edge and the second outer edge.
 3. The air cleaner as claimed in claim 1, wherein each fan blade has an air outlet angle of 60° to 68°, an air intake angle of 58° to 64°, and an extension angle of 54° to 64°, the number of the fan blades is 9-11; the air outlet angle of the fan blade is the included angle between an outer edge tangent of the fan blade and the diameter crossing the tangent point of the outer edge tangent of the fan wheel, the air intake angle is the included angle between an inner edge tangent of the fan blade and the diameter crossing the tangent point of the inner edge tangent of the fan wheel, and the extension angle of the fan blade is the included angle between the radius crossing the fan blade inner end of the fan wheel and the radius crossing the fan blade outer end of the fan wheel.
 4. The air cleaner as claimed in claim 3, wherein the air outlet angle of the fan blade is 64°, the air intake angle of the fan blade is 62°, the extension angle of the fan blade is 59°, and the number of the fan blades is
 9. 5. The air cleaner as claimed in claim 1, wherein in a radial direction of the fan wheel, a curved surface is formed between the fan blade outer end and the fan blade inner end; in an axial direction of the fan wheel, each fan blade is inclined along the airflow inlet toward the outer edge of the rear end plate to form an inclined surface that is a curved surface.
 6. The air cleaner as claimed in claim 1, wherein a central portion of the rear end plate is provided with a guide boss protruding toward the airflow inlet, and a guide slope is formed between an outer edge of the guide boss and the outer edge of the rear end plate.
 7. The air cleaner as claimed in claim 1, wherein the rear end plate is provided with a plurality of pairs of ribs corresponding in position to the fan blades for retaining the fan blades.
 8. The air cleaner as claimed in claim 1, further comprising a guide unit, the guide unit being mounted in the air duct and located between the air outlet and the motor; the guide unit including an outer mounting seat, an inner mounting seat, and a plurality of guide blades that are mounted at equal intervals between the outer mounting seat and the inner mounting seat; each guide blade having a guide fan inner end connected to an outer circumference of the inner mounting seat and a guide blade outer end connected to an inner side of the outer mounting seat, the outer mounting seat being mounted on a side wall of the air duct; a guide direction of each guide blade being deflected from an inner side to an outer side of the guide unit.
 9. The air cleaner as claimed in claim 8, wherein the guide blade outer end has a width of 18-22 mm, the guide blade inner end has a width of 28-32 mm, and each guide blade has a height of 37-41 mm.
 10. The air cleaner as claimed in claim 8, wherein the guide blade inner end has an air intake angle of 60° to 70° and an air outlet angle of 80° to 90°; the guide blade outer end has an air intake angle of 60° to 70° and an air outlet angle of 80° to 90°; the air intake angle of the guide blade inner end is the included angle between an inner edge tangent of the guide blade inner end and a rotation axis of the fan wheel, the air outlet angle of the guide blade inner end is the included angle between an outer edge tangent of the guide blade inner end and a vertical plane of the rotation axis of the fan wheel, the air intake angle of the guide blade outer end is the included angle between an inner edge tangent of the guide blade outer end and the rotation axis of the fan wheel, and the air outlet angle of the guide blade outer end is the included angle between an outer edge tangent of the guide blade outer end and the vertical plane of the rotation axis of the fan wheel. 